autotest/virt-test — pull request #1880 by ypu (2014-11-12 06:23:04+00:00)
Title: virttest.env_process: Add default value to kernel_extra_params related p...

...arameters

Add "" as default value for kernel_extra_params_add and kernel_extra_params_remove.
Otherwise it will report TypeError later when we try to add kernel options to them.